In 1986, Grau played a role in the television series All Is Forgiven.[5] Between 1986 and 1987, she played the character Corinne in a few episodes of the sitcom Cheers,[1] a show on which she had previously worked as script supervisor during seasons one and four.[6] Grau worked as a script supervisor on Fox Broadcasting Company's The Tracey Ullman Show (1987–1990), a variety show that featured among many things the first appearance of the fictional animated Simpson family.[7] This family was later given their own animated series on Fox, called The Simpsons, in 1989. Grau worked on that show as a script supervisor as well.[7] Grau also voiced some characters in The Simpsons. She is best known for lending her voice to Lunchlady Doris, who speaks with a "gruff voice" according to The Journal Gazette editor Dean Robinson.[8] This character appeared on the show with Grau's voice between 1991 and 1997.[9] Grau also worked as an actress on the animated series The Critic that was created by writers of The Simpsons in 1994. She voiced the chain-smoking character Doris Grossman, who is the make-up artist for the main character of the show.[10][11]

In 1992, Grau appeared in the supporting role of Hattie Rifkin in the film The Distinguished Gentleman.[12] According to Philip Wuntch, film critic for The Dallas Morning News, Grau "has only a few lines as a senior citizen with old-time political savvy, but she makes every vocal inflection count."[13]The Patriot-News‍‍ '​‍s Sharon Johnson called her "a delight as the feisty senior citizens' lobbyist who first recognizes Johnson as a winner."[14]

Grau worked as a script supervisor on the sitcom Good Advice in 1993, and played characters in the sitcoms Phenom and The George Carlin Show in 1994.[5] One of her last film appearances was a minor role in the 1995 film Babe, which is about a pig who wants to be a sheepdog.[1] She also appeared as the character Rose in the 1995 film Coldblooded that tells the story of a member of the Mob who is promoted to hitman against his will.[15]

On December 30, 1995, aged 71, Grau died from respiratory failure at a hospital in Hollywood.[1] "Team Homer", an episode of the seventh season of The Simpsons that aired on January 7, 1996, was dedicated to her memory.[8] Because episodes of The Simpsons are produced a long time before they air, Grau's last appearance on the show was in the episode "Lisa's Sax" that aired on October 19, 1997. Her character, Lunchlady Doris on The Simpsons was retired out of respect (similar to the retirement of Phil Hartman's characters). However, the character returned to the show after a decade-long absence in 2006 (voiced by Tress MacNeille).[16]